Reality and beliefs Please read!?

I'm a 23 year old mail. The past three years or so have been very unstable for me. I've gone back and forth on Christianity, postive thinking, surpressing feeling, meditation, mindfulness, and simply downright exhusting my mind! My question is, how can we as humans devlelop a solid belief system, while being open to the fact that our beliefs are simply choosen beleifts, and nothing is really "true". For example, I could choose to believe I'm an attractive or unattractive person, but in reality, these are both just beliefs and not truths. I've been told that I can create my reality according to the beliefs I choose to feed my subconscious mind, but how do I know if I've gone too far, especially if we are to have a belief that nothing is impossible. It doesen't seem logical to hold the belief that even if I eat terrible and smoke, to hold onto the affirmation and belief that " I live in a healthy body and am well". And what does irrational and delussional thinking really mean? For example, many might have said that THomas Edison had irrational and delussional beliefs about forming a light bulb, but clearly his belief that was consdered "Impossible" has changed life as we know it. Who is to stop me in believing in the ressurection of Jesus without beliving in hell and certain aspects of sin, while other Christians may say my beliefs are inccorect. I guess my question is, if reality is dependent on the subective beliefs that we CHOOSE to believe, instead of a truth that nobody agrees on, where do we draw the line when determing our own personal beleifs? Please help!